The present invention relates generally to plow systems for mounting on a multi-purpose vehicles, such as skid steer loaders and the like, wherein pressurized hydraulic fluid for operating hydraulic components of the plow system is obtained from the hydraulic system of the vehicle, and more particularly to a plow system including a hydraulic fluid diverter that allows hydraulic fluid to be recirculated back to a reservoir, preventing pressure build up in the hydraulic lines.
Many snow plow systems are designed to be removably mounted on the front of vehicles, such as jeeps, pick-up trucks, and the like. In such applications, the operation of the snow plow is controlled from the cab of the vehicle using a joy stick or other control device that is located within the cab of the vehicle. Such applications require that electrical wires pass through the firewall of the vehicle to provide electrical connections between the control device located within the cab to the electrical components, such as coils of hydraulic actuators, that are located near the front of the vehicle and/or on the snow plow. In addition, the electrical components of the snow plow use the battery of the vehicle as a source of electrical power, necessitating electrical connections between these components and the vehicle battery. Further connections are required between hydraulic components of the snow plow and the hydraulic supply of the vehicle. In most instances it also is necessary to attach a frame to the vehicle to support the snow plow and its hydraulic and electrical operating components. Thus, the removable mounting of a snow plow on a vehicle usually requires that several connections, both mechanical and electrical, be made.
In recent years, plow systems have been removably mounted on multi-purpose vehicles, such as skid steer loader-type vehicles. For example, U.S. Pat. No. 6,035,944 discloses a plow blade mounting system for mounting an adjustable V-plow blade on a skid steer loader-type vehicle and the like. This application provides a quick release-type mounting of the plow to the tool mounting plate of the skid steer loader. Although this arrangement simplifies the mechanical connections necessary for mounting a plow on a vehicle, electrical power for the plow is obtained from the vehicle battery and thus, connections must be made to the vehicle battery in addition to connections to the auxiliary hydraulic output of the skid steer vehicle.
A further consideration is that obtaining pressurized hydraulic fluid for operating hydraulic components of the plow system from the auxiliary hydraulic output of the skid steer loader places constraints on the operation of the plow system. The auxiliary hydraulic output must be deactivated whenever the V-plow blade is not being repositioned and must be activated by the operator when the plow blade is to be repositioned. Because the hydraulic controls of the skid steer loader are used to reposition the plow blade, the operator must be located in the cab of the skid steer loader to make any adjustments in the angling of the plow blade.
Moreover, access to and egress from the cab of the skid steer loader typically is through a door that is located on the front of the skid steer loader as is known. Because the upper edge of the metal mounting panel of the plow is located just forward of the door, the operator typically uses the upper edge for footing whenever entering or exiting the cab, which can present a hazardous condition if the operator should loose footing.
The invention provides a plow system for use with a vehicle having a hydraulic system that supplies hydraulic fluid under pressure continuously to a hydraulic fluid outlet when the hydraulic system is operating in an active mode. The plow system includes a repositionable plow blade, a hydraulic actuator coupled to the plow blade and a hydraulic control system including a pressure head that supplies hydraulic fluid from the fluid outlet to the hydraulic actuator for repositioning the plow blade. A bypass device diverts hydraulic fluid away from the hydraulic actuator when the hydraulic system is operating in the active mode and the plow blade is not being repositioned.
In one embodiment, the vehicle can be a skid steer loader and the hydraulic fluid outlet is an auxiliary hydraulic output of the skid steer loader.
In such embodiment, the bypass device allows the auxiliary hydraulic system to be maintained activated even when the plow blade is not being repositioned. In one embodiment, the bypass device is a normally open valve that is connected between a fluid inlet and a fluid outlet of the pressure head, allowing hydraulic fluid to be recirculated back to the reservoir to thereby prevent pressure build up in the hydraulic fluid flow path to the hydraulic actuator whenever the plow blade is not being repositioned.
In one embodiment, the plow system includes wireless remote radio frequency control of the operation of the bypass device. The plow system includes a wireless remote control transmitter which transmits coded radio frequency signals and a wireless remote control receiver which receives the coded radio frequency signals. In response to the coded frequency signals, the receiver provides an activating signal for causing the bypass device to allow hydraulic fluid to be supplied to the hydraulic actuator or actuators for repositioning the plow blade. Preferably, the transmitter is a self-contained, battery-powered portable device locatable within a cab of the vehicle or at a location outside of the cab of the vehicle.
In another embodiment, the plow system includes a voice-actuated control.
Further in accordance with the invention, there is provided a snow plow system for use with a skid-steer loader having an auxiliary hydraulic output. The snow plow system includes a repositionable V-plow blade, a support structure supporting the V-plow blade and hydraulic actuators for repositioning the V-plow blade. A control unit supported by the support structure operates the hydraulic actuators to reposition the V-plow blade. A hydraulic control unit includes a pressure head that is interposed between the auxiliary hydraulic fluid outlet and the hydraulic actuators. The pressure head defines a first fluid flow path for supplying hydraulic fluid under pressure to the hydraulic actuators for operating the hydraulic actuator and a second fluid flow path. A bypass device diverts hydraulic fluid away from the first fluid flow path and returns the hydraulic fluid to a hydraulic fluid reservoir when the hydraulic system is operating in the active mode and the V-plow blade is not being repositioned.
In accordance with another aspect of the invention, there is provided a plow system for use with a skid-steer loader wherein access to and egress from a cab of the skid steer loader is through a doorway located at the front of the skid steer loader. The plow system includes a plow blade and a support structure supporting the plow blade to enable repositioning of the plow blade. The support structure includes a vertically extending panel, the upper edge of which is located forward of the doorway, enabling an operator to use the upper edge of the panel for footing upon entering or exiting the cab. The upper edge of the panel defines an anti-slip surface. In one embodiment, the upper edge of the panel is of patterned steel providing the anti-slip surface. In another embodiment, the upper edge of the panel includes a layer of non-slip material to provide the anti-slip surface.